1. Field of the Invention
The present invention relates to a cleaning method in the process of forming a pattern, such as a wiring pattern, on a substrate, a film deposition method, and a film deposition apparatus.
2. Description of the Related Art
Formation of films, such as wires for semiconductor and display devices, on substrates and patterning thereof are extremely important in various industries. In particular, wiring of conductive metals is widely employed in the various fields, such as for wiring on semiconductor substrates and for electrodes in display devices. Currently, in the methods which are predominantly employed, film deposition and patterning are performed separately. For example, in a conventional method, a wiring material is formed on a substrate by vapor deposition, a resist is applied over the entire surface of the vapor-deposited film, a lithographic process including exposure and development is performed to form a resist film having a predetermined shape, and patterning is performed by etching the vapor-deposited film through the resist film. In the methods using lithography, a large number of steps is generally required, resulting in an increase in cost. Moreover, many problems must be solved in such methods. For example, higher aspect ratios must be dealt with, and higher throughput must be achieved. In order to overcome the problems, methods are known in which fine particle films are formed on substrates or the like by gas deposition techniques.
The gas deposition techniques are disclosed, for example, in Japanese Patent Nos. 2524622, 1595398, and 2632409. A gas deposition technique will be described below with reference to FIG. 1. FIG. 1 is a schematic diagram showing a fine particle film deposition apparatus using the gas deposition technique.
As shown in FIG. 1, fine particles in a fine particle generation chamber 1 are introduced into a film-forming chamber 2 through a transport pipe 3 together with a gas, and the fine particles and the gas are sprayed at a high speed from a nozzle 4 provided on the end of the transport pipe 3. A fine particle film is thereby formed on a substrate 10. Vapor atoms generated from a material 8 for generating fine particles, which is a vapor source in the fine particle generation chamber 1, are rapidly cooled because they collide with an inert gas fed into the particle generation chamber 1, and are transported through the transport pipe 3 together with the inert gas while grain growth is taking place. The material vapor is generated in the fine particle generation chamber 1 by heating the vapor source with a heating mechanism 5. Any one of various known heating techniques may be used for the heating mechanism 5.
In FIG. 1, reference numeral 6 represents a vacuum pump for evacuating air from the fine particle generation chamber 1, reference numeral 7 represents a carrier gas cylinder for feeding the inert gas, and reference numeral 9 represents a substrate-moving mechanism for moving the substrate 10 in order to shift the film deposition position on the substrate 10.
As an example of formation of a wiring pattern using a gas deposition technique, Japanese Patent Laid-Open No. 05-136128 discloses a method in which circuit wiring composed of a conductive fine particle film is formed by a gas deposition technique.
Japanese Patent Laid-Open No. 07-096260 discloses a method in which cleaning is performed by spraying fine particles of a sublimable substance at a high speed. In the method, by controlling the spray intensity, cleaning and cutting can be simultaneously performed.
In general, film deposition is greatly influenced by cleaning before deposition. If cleaning is insufficient, adhesion between a substrate and a film is degraded, resulting in a decrease in durability. Furthermore, the state before deposition must be stable in order to stabilize the film deposition. Even if cleaning is performed stably, the state before deposition may become unstable due to changes with time. In order to control the state before deposition, cleaning must be performed immediately before deposition. Furthermore, although the entire surface of the substrate is usually cleaned, since some of the materials which have been provided on the substrate may be easily influenced by cleaning, cleaning of the entire surface of the substrate is not always the most suitable method. The present invention has been achieved to overcome the problems described above. It is an object of the present invention to provide a method in which film deposition and patterning are performed simultaneously using the advantage of a gas deposition technique, the film deposition is performed stably by stabilizing the state before the film deposition, and cleaning is performed selectively on necessary parts so as to avoid damage to the other parts of the substrate.
In accordance with the present invention, a film deposition method includes the steps of (A) preparing a first chamber, a second chamber, and a transport connector which connects the first chamber and the second chamber with each other, (B) setting the pressure in the second chamber lower than the pressure in the first chamber, and (C) introducing a plurality of kinds of particles into the second chamber using a differential pressure between the pressure in the first chamber and the pressure in the second chamber so that the plurality of kinds of particles collide with a substrate placed in the second chamber to form a film on the substrate. The plurality of kinds of particles include particles of a sublimable substance and particles of a material for forming the film on the substrate in the second chamber.
Preferably, the particles of the material for forming the film are preliminarily placed in the first chamber.
Preferably, the particles of the material for forming the film are generated in the first chamber.
Preferably, the sublimable substance is a substance selected from the group consisting of carbon dioxide, iodine, camphor, and naphthalene.
Preferably, the particles of the sublimable substance are fed into the transport connector located between the first chamber and the second chamber.
Preferably, one end of the transport connector is placed in the first chamber and the other end of the transport connector is placed in the second chamber, the end of the transport connector placed in the second chamber being provided with a nozzle.
Further objects, features and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings.